Kline made a modern version of Marx's 1998 with updated trucks, frame , and motors.
Search for K-Line s2 to start: 'bout 100 on the 'Bay for about $75 or less.
I've looked at them. My take on them:
* They have the full length side handrails as per the prototype.
* The end cab windows are already opened and glazed.
* End rails are more fully developed.
* No mechanical E-unit.
* They seem to be perched higher on their trucks, giving them a bit of a "high water" look.
* The open ended pilots are a bit of a bother to my eyes.
* Suspect the can motors will react to rheostat slider transformer power transmission just like my K-Line MKT FA's of the past: Jack rabbit start on account of the 5-6 starting volts of a conventional transformer. I had several can-motored engines that suffered from this malady "back when". (The Lionel #8626 4-6-4 steam engine was the first can-powered engine I noticed this on. By contrast, the can-motored RMT Beep ran really nice on my ZW at the time.)
FWIW: I think I could be happy with an RMT Bang.
For the sake of comparisons, here's a picture of a K-Line "S2":
And here's a Marx "1998":
AND... for the heck of it, here's an RMT Bang:
The RMT has many pros to recommend it, but they're almost 6 times more expensive than either the K-Line or a Marx. (Nearly $300... if you can find one.)
Of the three, I like the "stance" of the Marx better. I think the lower height fits the foreshortened model better.
However, with all this nitpicking over traditional-sized trains running on 3-rail track... (let that soak in for a second)... I think it should be obvious my GnC* syndrome is poking-up its illogical and inconsistent head yet again.
* "Gnats n' Camels" syndrome. That is, when it comes to my weird 3-rail tastes, I'll swallow a camel and gag at a gnat.
Clear as mud?